Elevator



Magch 1927. J' DUNLOP 1,619,405

I ELEVATOR F4 Filed March 12, 1925 3 Sheets-Sheet 1 Much 1,1927.1,619,405 J. DUNLOP l ELEVATOR Filed March l2, 1925 3 Sheets-Sheet 2Iig@ l@Q50 6@ 115.11. -l-- 6 62 Etz: "u

LTamm rUzmZoy?,

J. DUNLOP March 1, 1927.

mmvuon :s sheets-sheet iled March 12, -1925 maw RS NQ -JZQ M Y @suchelevators.` lAi'iotlier object ,therefore re- Pahtenterd Mar. 1, 1927.

unirsi); STATES PATE-Nr oI=1i-1i 3s ELEVATDR.

Application filed March 12, 1925.` Serial/No. 14,7857.

`'jjlrevpresentpinvention relates to improvements in elevators.

, Y In industrial establishments,where large or heavy loadsare'frequently to be carried by elevators, large freight elevators areneeded.I During most of the time, however, there isn'butflittleusefor alarge elevator, anda v smaller elevator would befinore desirable and'vio - K4economical.",YThe .primaryV object of the inJ gvention',',therefore, is to provide' av cdouble vuniti Lfele'vatojr having twocages lwhichy can ybe operated independently, or operatedjointlyasdesired. l Y

;l Inpperating two cages as one, however, considerable lditliculty isYmet iii maintaining rthetwo Vplatformsat the saine level, i. e. causingthefcages to travel through ia uniformmdistance" at "aiinifo'rm speed.Such a result is',notfonly desirable, `but is necessary '.for thesncc'essful and ,practical operation ot y:sides inthelprovisionfofnovelmeans for {finechanically connectingparts of the two `elevaltor4 iinits,fa`ndiineans Vfor lsynchronizing 'z the operationof thefdriving means soas to .canse the lcagesto travel through a uniform i distanceata-uniform speed.

g A'furtherobjectresidesfin the provision of y. means forA connecting.and :disconnecting the two counterweights, and'in the speciiicconstruction of said means.

Another ob]ect is to provide Aan elevator of `thefabove character whichis equipped with .suitable interlocking ineans in the control Si.circuits `such Ithat, when thev counterweights [areiconnectedf the cagesVcannot be operated v independently, and when the counterweiglitselevator having two independent lunits, `each 'K aredisconnected thecages cannot be operat- 'edfjontly A morel specific object is tfop-i'ovidea novel lot l which comprises afcage, driving means fory.,thecage, ancL a controller therefor, and

` which are adapted tobeoperated separately ,bymeans"oftheii',individual controller, or Vjoint-ly bymeanso'f oneotsaidcontrollers. v4Ancillary objects" andA advantages will be- Y' comel'apparentas the description proceeds.

Y In the accompanyingdrawings, Figure l y. is a lvertical sectional Viewot an elevator hatchwaytor an elevator constructed in acv- "cordancewith rmy invention.

' Fig. 2 is a sectionalviewtaken along line.

' Fig. 3 is a sectional view taken along line S of Figi.y

F igxfi is a lfront view of, the counterweights. l

Fig. 5 is a side view of the counterweights. y

G is a yhorizontal sectional view of the counterweights taken along`line 6 6 of Fig. 4.

Figur? is a sectional view taken along line T47 of Fig. 6. f

Fig. 8 is an enlarged `fragmentary front. view of the locking membersforA the counter- `weights and the interlocking switches controlledthereby. i

Fig. 9 is a diagrammatic represent-ation 4ot the control circuits foradouble unit ele- 'vator embodyingrthe features of my invention,thevcii'cuitsbeing connected for joint operation'. Y

yVihilethe.invention is susceptible of various ,modifications andalternative constructions, 'I Yhave shown in tlieaccompanying drawingsand will'herein describe iii detail `tlie preferred en'ibodinient, butit is to` be i understood thatl do not thereby intend to limit theinvention to the particular forni disclosed, but aim to cover allmodifications and alternatiye constructions -falling within the spiritand scope ot the appended' claims.

In itslexemplary embodiment, the 'invention contemplates the provisionof tivoselectric elevator unitsot which Ithe cagesare operable in asingle liatchway and are adapt-v ed to be operated independently,or-jointly as a single platform, means `for locking the counterweightstogether for joint operation, and electric interlocks inthecontrolcircuits -ot the two elevator units for preventing independentoperation oit the cages and for synchronizing their movements when thecounterweiglits,are lockedtogether, butl pei'- initting independentoperation oi ,the cages when the counterweights are .discon nected nfrom each other.

Thev Zener/00", structure.

is provided with suitable guide shoes 17 at the trent and rear engagingvertical guide rails 18 in the hatchway. The adjacent walls of the cagesare provided with vertically sliding gates 19 which are adapted to beraised to permit the joint use ot both platforms.

hounted on a door 2O at the top of the hatchway are two tractionmachines, one for each cage. l/Vhile these machines may be oi anysuitable construction, in the present instance they comprise electricalmotors 21. and 22 respectively which are provided with electromagneticbrakes 23 and 24, and which are directly geared to two traction drums 25and 26 respectively. The latter are rotatably supported by pedestalbearings 27 which with the motors and the brakes are mounted en two baseplates 2S. lwound on the drums 25 and 26 are cables 29 and 30respectively, the like ends ot which are connected in one instance tothe 15 and 16 Vand in the other instance to two count ights 31 and 32respectively.VV The counter-weights ari` proifided with suitable `auideshoes 553 which engage two sets ot vertical guide rails 34. These setsot rails are positioned in parallel and closely spaced relation topermit positioning the counterweights next to each other7 and aresupported centrally on the rear wall 11 of the hat-chway to simplify thearrangement oiE the tract-ion machines. In leading to thecounterweights7 the cables 29 and 30 are directed respectively over twosheaves 35 and 36 rotatably mounted in a box 37 just below the door 20.Since the counterweights are mounted to move in closely spaced paths,one sheave is positioned below the other to avoid interference betweenthe two. The base plates 28 ot the traction machines are inclineddiagonally with respect to the cages 15 and 16 and ar-e arrangedlperpendicularly to each other to direct the cables downwardly,centrally oi the cages and of the counterweights.

The coul-n terwez'gns.

upper ends of the rods 42 and between the cross structure 39 and theuppermost weight 41. Upon changing the number of weights 41 on thecounterweight, sleeves 44 ot proper length are substituted. Theconstruction ot the counter-weights thus 'far described is old and wellknown, and 'forms no part ot the present invention.

Adjustably mounted between the channels 38 ot each counterweight is across head which comprises an out-er plate 45, and an inner plate 46.The inner plates of the two counterweights are located adjacent eachother when the latter are positioned side by side. The inner and outerplates ot each counterweight engage opposite legs of both channels 38,and. are adapted to be clamped thereto by a plurality of bolts 47. Thesebolts extend through the plates next to the channels. w extendingbetween the channels 38 are sccured between the plates fil-5 and 46 bybolts 49 extending through the latter, and are separated vertically bymeans ot spacers 5() positioned between their opposite ends. T hebinding rods 42 extend loosely. through holes provided therefor in theblocks 4S and the spacers 50. Two adjusting rods 51 connected to theupper cross structure 39 extend downwardlyY through alined holes in theopposite ends ot the blocks 48 and in the spacers 50, and are securedthereto by nuts 52 which permit the cross head to be vertically adjustedin the counterweight.

The blocks 48 ot the two counterweights.

are formed on' their adjacent sides with lateral projections 53 wnichextend through longitudinal slots 54 in the inner plates 46. Pivotallymounted on vertical pins 55 and between the blocks 48 in thecounterweight 31 are two connecting lor locking members 5G. Thesemembers are adapted to be positioned completely within the counterweight31 when the counterweights are disconnected, and are adapted to be swunginto the horizontal space between `tlu'blocks 48 in the -counterweight32 to connect said counter- 'welffhts for movement as a unit. ro avoid fditiitulty Vin connecting the cminterweights when slightly out ofhorizontal alinement the Ytree ends ot the niember 56 are beveled. Thepins 55 preferably are formed with enlarged portions 57 on which theconnecting members 56 are mounted, and extend through the blocks 4S towhich they are non-rot'aably secured by nuts 58.

To provide suitable means vfor actllating the connecting membersh thelatter are 'formed with right handand lett hand gear quadrants 59 andti() respectively which mesh with a worm G1 journaled in the outer andinner plates ot the counter-weight ill. ()ue end of the wormshattezitends through the outer plate 45, and is provided with a squaredend 62 to facilitate adjustment of the worm. The outer plate` 45 isformed with two spaced openings 63 next to the quadrants 59 and 60 topermit the latter to project slightly beyond the blocks 4S.

Mounted in the outer plate 45 and on the Two heavy elongated blocks 48lfit) l il) Y upper block 4816i the counterweight 31 are Atwointerlocking switches 64 zuid 65 each oi Awhich is provided with a.inoylble Contact inenibei 66. f The lContact:ineinbeis 66 are adepted'tobe actuated by cain faces 67 and ,68 forii'iedon the upper edges of thequad rants 59 and respectively. These yCain facesnreso 'arranged'v thatwhen the locking nier'n'b'ers 56 are inoved'iiito engagement with itli'ecounterweightg 32 the switch 65 will be f jo'pei'ed and the kswitch 64will be closed, and

v that when said ineinbers are positioned conipl'etely within4 y. thecounterweight 31`tlie switch 64 willbe open'eiid vthe switch 65 closed.I

' The control circuits.

i L yReiterr'iiti'g 'to Fig. 9 twosets ot control circuits', one )foreach Yelevator unit, connected by sufitabley interlocking switches iorJoint operation are shown. The position "of eachof the interlockingswitches when the control circuits are disconnected for independentoperation ot the elevator units is 'illustrated in dotted outline. Sincethe two sets of control circuits are substantially lalileioiilyv oneVwill be described in detail, vand the corresponding parts of the otherwill A be designated by like-numerals prinied.

f E'achelevator unit coinp'iises ay car switch 69, consisting of avcontroller 70 andv two V"ciita'ets 1v 'z'ind 72 ywhich' controls up7and down`` directional switchesr 73 and 74 rethej elevator operation. Iinterlocking switches are in theirr dottedposispectivlely,A Thedirectional switches each c"or`i' trol si'k potential switch 75Uand twoaccelerating switches 7 6Nand 7 which are opera'ble' in t-iin'edsequence to progressively c ut out resistance in two of the' inotorwind- -i'ries The wiring is best described outlining Assuiiiing thattlie l tions'to 4'p'ei'init independent operation oi' the "clevtiterunits',lj,in"d that the controller 70 is i'noyfedin'to engagement withthe Contact 72, "theffollowi'n'g control circuit is established:

' ,fronf'the 'inzi'in L?, througlr wire 78' passing the controller 70;thenthrough thel Contact 72, a'wire 84 and a coil 8,5 of the up dii yrectional switch' 7 3; and then throughwire 86 passing throLighv ayplr'iralityl of safety defvic'es 87, an interlocking switch 88 Vand a g166 fuse 89 to. tlhe inain L3.

.73 which establishes the following control Excitation 'of the coil 85closes the switch 4circliit.s I,frein thei'iiain L3 through a wire 90,switchl contacts'l v91, anda wire 92 to the brake Winding 23 and.Vthrough resistances "A" and BV to (incensi-ing @fue from' 21;

frein the inain vL2 throughawire 93, switch contacts '94. and a wire 95to' the brakewinding 23; and i'i'oin the inain L1 through a wire 96, acoil 97 ot the potential switch 7 5, the wire 95, the contacts 94 andthe wire 93 to the inain L2. y

Excitation oil the coil 97 effects a closure ot' the switch`75 whichestablishes the following Control Circuits: froin'the'inain L1, throughthe wire 96, switch contacts 98, and a wire 99 to the brake winding` 23`and through resistances C and D to another winding of the i'iiotor 21;and from the inain L2, through the wire 93, the switch contacts 94', thewire 95, switch 'contacts 100, and a wire 101 to the third windingof theiiiotor 21. Upon the establishment of these circuits the brake 23 isreleased, and the motor 21 begins to operate to inove the cage 15 in anup direction. 1

Shortly after the niotor21 begins to operate, a pair of switches 102 and103 controlling the accelerating switches 76 and 77 respectivelyare'closed in tini'ed sequence and in the order na'ined by 1 anysuitable means (not shown). 'Closure of the switch 102 coin- `pletes'the following circuit: troni the wire 95, through the switch 102, and acoil 104 iior the accelerating switchf76 to the wire 92. Closure of theswitch 76 short circuits .the resistances' A and Cv in the wires 92 and99 through switch contacts 106 and'107 respectively thereby acceleratingthe speed of the motor 21.

Subsequent closure oit the switch 103 vcoinpletes the following circuit:roin the wire 95 through the switch 93,' and a coil 108 for the switch77 to the 'wire 92. Excitation ot the coil 108y closes theacceleratingswitch 77 which short circuits the resistafiices B and D inthe wires 92 and 99 through switch con-V tacts 109 and 110respectively.I thereby increasing the speed of the i'notor 21 to'ullspeed. y Y

To stop the cage the controller is' inoved into its neutralpositiongtheieby breakii'ig the control circuit through the coil 85, andreturning all parts of :the system to initial position.

Upon inoveinentof t-lie controller 70 into engagement with the contactl71, a control. circuit through a wire 111 and a coil 112 for the downdirectional switch 74 is coinpleted. The switch 74 when closed serves toconnect the wires 92 and 95 through switch contacts 11B und 114 to thewires 93 and respectively, thereby rerersing the connection of thesewires with the mains L2 and L3A and causing the i'not-or 21 to incre thecage 15 in a down direction'.l

When the elevator units are to be operatedv jointly, the counterweig is31 and 32 are connected by the locking ineinbers o6, the gates 19are'iaised, and the interlocking switches are thrown into' the positionsillustrated in full outline in Figure 9. In practice, the interlockingswitches, excepting switches (Sil, 65 and 7 S) are all controlled by asingle actuator, and are, therefore, operated together to place theelevator unit either in condition for independent operation or incondition t'or joint operation.

Upon connecting' the counterweights 31 and 32, the switch 65 'is openedthereby preventing independent operation ot' the cages and 16, and theswitch (i/l is closed thereby permitting joint operation ot' the cagesas will be hereinafter described.

Upon raising the gates 19 the switches 79 are opened thereby preventingindependent operation oit the cages.

`Upon thro-wing' the interlocking switches into lposition ior jointoperatioin of the cages, the switches and 79 are shunted by theinterlocking' switch 80 thereby permitting joint operation when thegates 19 are up and the switch '65 is open. The controller is shnntedand the safety devices switch 83 connected by and usesin the nected inseries switches 83 and switch115. The

wire 11Ga through the switch 64 to the controller 70. The switch Gthuscontrols the circuit through the controller 70, and must be closed topermit joint operation ot' the elevator units. This necessitatesconnecting the counterweights 81 and 32.

Since the controller 70 is rendered inoperativc, the wires 84 and 111are connected by wires 116 and 117 leading through interlocking switches118 and 119 to the wires 84 and 111 respectively, to connect the coils85 and 85 in parallel to the contact 72 and the coils 112 and 112 inparallel to the contact 71.

The wires 86 and 86 leading' from the coils 85, 85, 112 and 112 to themain L3 are connected by an interlocking' switch 120, and the safetydevices 87 and 87and the i'use 89 in said wires are connected in seriesby the interlocking switches 88 and 88 and an interlocking switch 121.It will be evident that upon movement ot the controller 70 intoengagement with the contact 72, the switches 78 and 73 will besimultaneously actuated to eii'ect movement ot the cages 1li and 18 inan up direction, and that upon movement et the controller 70 into engagenient with the contact 71, the switches 74e and 7st will besimultaneously actuated to etllect a down movement of the cages. All ot'the safety devices in both elevator units are connected into the jointsystem.

To obtain a like acceleration of the two motors 21 and 22,theaccele'rating switches 7 6 and 77, and 76 and 77 are placed under thecontrol of the time switches 102 and 103 by connecting the coil 10ethrough a wire 122 and a switch 123 to the coil 104:

to shunt the switch 102', and connecting the coil 108 through a wire1211 and a switch 125 to the coil 108 to shunt the switch 103'-,

It will be evident that I have provided a highly advantageous elevatorcomprising two independent elevator units which can be operatedseparately or which can be -asily and quickly converted into a singlesystem. By connecting the counterweights for joint movement, the cagescan be driven through a substantial distance at exactly t same level andno breakage or injury will result it one cage should move at a greaterspeed than the other. In general he elevator is extremely simple inconstruction, and is highly eilicient in operation.

l claim as my invention:

1.1111 elevator having, in combination, two independent elevator unitseach of which comprises a cage, a counterweight, traction means, and aset of control circuits Vlor said n'ieans, a. hatchway l'oi' said cagesl said counterweights, n'ieaiis ttor connectsaid counteiwveights, andmeans for con ting said sets of control circuits into a single systemunder one control.

2. An elevator having', in combination, two elevator units each of whichcomprises a cage, a counterweight, driving means for said cage, and aset of control circuits for said means, a hatchway for said cages, meansiter connecting said counterweghts, and means tor connecting said setsof circuits to convertthen'i into a single system for operating saidcages jointly, said last mentioned means including a pair otinterlocking switches controlled by said means 'for connetting` saidcounterweights.

3. An elevator having', in combination, two independent elevator unitseach of which comprises a age, a counterweight, means for driving saidcage and counterweight, and a set of control circuits including a carswitch, a hatchway t'or said cages, and means for connecting said setsoi control circuits to convert them into a. single system under theexclusive control ot one of said car switches `for operating said cagesjointly at the same level and at a uniform speed.

4l. An elevator having, in combination, two elevator units, each ofwhich comprises a cage, a counterweight, means for driving said cage,and a set of control circuits including' a. car switch, and each ofwhich is independently operable, a hatchway tor said cages. means torconnecting said counterweights and means for connecting said sets ofcontrol circuits to convert them into a single system under the controlof one of said car switches for the joint operation of the cages, theconnection of said counterweights serving to maintain said cages to thesame level throughout their joint movement.

An elevator having, in combination,

two. independent elevator units, each o which.y comprises cage, acounterweight,

`means for driving said cage, and control ciruitsforsaid driving means,said counter- Weights being mounted .to move closely past l each other,a `single hatchway in which said i @ases are. deposed andmeans for001111665* ingand disconnecting said counterweights to place saidelevator units in a condition Jfor joint operation or in a. ,conditionfor independent operation respectively.

6 A11 elevator having, ,1,11 Combination, two independent elevatorunits, each of which, 'comprises cage, a coniiterweight,

.meansfor driving saidcage, and control circuits 'fel-said drivingmeans, mea-11s for C911- secties @Qirespendingiarts 0f the tw@ .units toplacesad. units in a condition 01". joint operationwith said cagesmoving at the Same level, and meansV torconnecting said @mitral circuitsinto 11 Single System fol* synchronizing the operation yof 4said drivingmeans. Y

7. An elevator having, in combination,

ytwo lindependent'. elevator units each ot .which` comprises a cage, acounterweight,

. and means for driving said cage, and means for` connectingcorresponding. parts or' Vsaid tvvo units ,to place them in condition orjoint operation in which the cages are maintained at Vthesrame levelthroughout their .said coiinterwe joint. movement.

.8. An@ elevator. having, in combination,

two elevator unitsI each of whiclicomprises 1 a counterweight, a. cage,and driving means therefore, and means connecting saidv counterweightsto inoveas a unit, ythereby serving to'causesaid cages. to move jointly,and to maintain, cages at Ithe samedevel throughout such joint movement.

"An,ele'vator` having, in combination, two elevator'iinits, each ofwhich comprises a cage,'a counterweig'lit, and means fordrivingtliegsaine, ai liatcliwaxy for said cages and Y Ydriving means,a'ha't'chway for said cages I connected.

ands id counterweighta means for connecting the v.counterweights tocause them to Ainove asa unit and thereby maintain said cages aty thesainev levelkfor joint movement, and 'interlocking means forming part ofsaid sets of control circuits and' controlled by saidl last `nffentionedAmeans for preventing jointr operation :when-the counterweights. are

Vvdisconnected,and for preventing independ entl operation when thecounterweights are ll. An elevator having, in combination, two elevatorunits, each of which comprises acage, a. counterweight, means fordriving said cage, and a set o'li' control circuits for said drivingmeans, a .single hat'chway for said cages, and means for connecting saidcounterweights to move as a unit, thereby serving to maintain said cagesat the saine level throughout their joint movement in said liatchway. l

l2. An elevator having, in combination, two elevator units, each ofwhich comprises a cage, a. counterweight, means for driving said cage,and control circuits for said means, said cages being supported formove# mentrin closely spaced paths, gates in the adjacent sides of saidcages, switches controlled by said gates and forming part of the controlcircuits of eachmunit, said switches preventing independent operation ofsaid units when said gates` are open, and means for mechanicallyconnecting said units for joint operation. l

13. An elevator having, in combination, two elevator units, each ofwhich comprises a cage, a counterw ight, means for driving said cage,and control circuits for said means, said cages being supported formovement closely past each other, gates in the adjacent sides of saidcages, switches controlled by said gates and forming part of said conrol circuits .of each unit, .said switches preventing independentoperation ot said units when said gates are open, and means forconnecting saidvcounterweights to move as a unit to maintain said'cagesat the same level throughout their joint movement.

H. An elevator having,'.in combination, two ele vautor units, each ofwhich comprises a. cage, a counterweight, means for driving said cage,and control circuits for said means, gates in the adjacent sid-es ofsaid cages, switches controlled by said gates and 'forming part of saidcontrol circuits of both units, said switches preventing independent opeation of said units when .said gates are open, means for connecting said.units to permit joint operation thereof, and means for connecting saidcounterweights to move as a unit to maintain said cages at the sainelevel throughout their. joint movement.

l5. An elevator having, iii-combination, two elevator unitsfeach oiwhich comprises a cage, a counter-weight, and means for driving .saidcage, and a set of control circuits for said driving means, a hatchwayin which said cages are mounted tor movement side by side, gates in theadjacent sides of said cages, switches controlled by said gatesandforming part of cach set or" control circuits,

said switches acting to preventindependent operation of said unitswhensaid gates are open, means for connecting said counterweights,f and.interlocking switches controlled by said connecting means and foriningpart of said sets of control circuits, said interlocking switchesserving to prevent independent operation oi said units when saidcounterweights are connected and serving to prevent joint operation otsaid units when said ycounterweights are disconnected.

16. An elevator having, in combination, two elevator units each ofAwhich comprises a cage, a counterweight, means for driving said cage,and a set of control circuits ttor said driving means, means forconnecting said counterweights, and switch means controlled by saidconnecting means and torining part of each set of control circuits, saidswitch means serving to prevent independent operation of said units whensaid connterweights are connected.

17. An elevator having, in combination,

n two elevator units each otwhich comprises CJD a cage, a counterweight,means for driving said cage, a Iset ot control circuits for saiddriving` means and including a car switch and a series of safetydevices, means for connecting said counterweights, switch meanscontrolled by said connecting means and forming part of each set ofcontrol circuits, said switch means serving to prevent independentoperation of said units when said counterweights are connected, and topres v-ent joint operation of said units when said counterweights aredisconnected, and means including a series olf interlocking switches forconnecting various parts ot' said two sets of control circuits to placeboth sets under the control of one car switch, and to connect the safetydeviccs'o'l both sets in the joint system.

18. An elevator having, in combination, two elevator units each of whichcomprises a cag-e, a counterweight, means for driving .said cage, and aset of control circuits 'for said driving means and including a carswitch and a series of safety devices, means for mechanically connectingcorresponding parts of the elevator structure of the two units, switchmeans controlled by said connecting means and forming part of each setof control circuits, said switch means serving to prevent independentoperation of said units when said parts are connected, and to preventjoint operation of said units when said parts are disconnected, andmeans including a lseries of interlocking switches for connectingvarious parts of said two sets ofV control circuits to place bothsetsunder the control of one car switch, and to connect the safetydevices of each set in the joint system. Y

19. An elevator having, inv combination, two elevator units each ofwhich comprises a cage, a counterweight, means forV driving said cage, aset et control circuits for the driving means and a series of safetydevices, means for mechanically connecting corresponding parts of theelevator structure of the two units, switch means controlled by saidconnecting means and forming part of each set of control circuits, saidswitch means serving to prevent independent operation of said units whensaid parts are connected, and to prevent joint operation of said unitswhen said parts are disconnected, and means including a series o'lfinterlocking switches for connecting various parts of the sets ofcontrol circuits to convert both sets otl control circuits into a singlesystem including the safety devices in both sets.

20. An elevator having, in combination, two elevator units each of whichcomprises a cage, a counterweight, means for driving said cage, and aset'of control circuits for the drivingmeans, means 'for mechanicallyconnecting corresponding parts of the elevator structure of the. twounits, and switch means controlled by said connecting means and formingpart of each set oi control circuits, said switch means serving toprevent independent operation of said units when said parts areconnected, and to prevent joint operation of said units when said partsare disconnected.

2l. An elevator having, in con'ibination, two elevator units, each ofwhich comprises a cage, a counterweight, means 'for driving said cage,and a set of control circuits for said driving means and including a setof safety devices, means for connecting said counterweights, and meansfor connecting various parts of the two sets olc control circuits toconvert them into a single system including said safety devices.

22. An elevator having, in combination, two elevator units cach of whichcomprises la cage, a countcrweight, means for driving said cage, and aset of control circuits for said driving means, means for connectingsaid counter-weights to connect said units for joint operation, andmeans for connecting parts of said sets of control circuits to convertsaid sets into a single system.

23. In a double unit elevator, in combination, two counterweightsadapted to be pol sitioned side by side, each counterweight having avertically adjustable head, and locking means in one head adapted to bemoved into engagement with the other head to connect saidcounterweights.

24. In a double unit elevator, in combinaion, a pair of count-erweightsdisposed for movement in closely spaced parallel paths, eachcounterweight having a head, a pair of locking members pivotally mountedin one ot said heads and being adapted to be swung into engagement withthe other head when said counterweights are positioned side by side,gear means for actuating said locking members, and a pair of switchesone of V,which is controlled by each locking member.

25. In a double unit elevator, in combijnation, a pair of counterweightsadapted to be positioned side by side, a pivotal locking member mountedon one counterweight, and means for pivoting said locking member intoengagement with ythe other countervveight when said counterweights arepositioned side by side.

26. In a double unit elevator, in combination,=tWo counter-Weightsadapted to be positioned closely together, a. pair of locking membersivotally mounted in one of said counterweights and Vadapted to engagethe other of said counterweights to connect the ltwo, and'gear means foractuating said members. Y

27. In a double unit elevator, in combination, a pair of counterweightsadapted to be positioned-in closely spaced relation, a locking memberpivotally mounted in one of said to engage or disengage saidcounterweights.

28. In a double unit elevator, in combination, two counterweightsadapted to be positioned closely together, each counter-Weight havingahead, a pair of locking members pivotally mounted in one oi' said headsand adapted tobe moved into engagement with `the other of said headsto'lock said counterweights together, each locking member having a gearquadrant', and a Worm gear meshing' ivith said gear quadrants andadapted to actuate them in either direction to lock or unlock saidcounterweights.

,29. In a double unit elevator, in combi4 nation, two countervveights,one for each unit, and means for mechanically connecting saidcounterweights. i

30. In a double unit elevator, in combination, a pair of counterweightsadapted to be mounted side by side, a head adjustably mounted in eachcounterweight, locking means in one head adapted to be moved intoengagement with the other head to lock said counterweights together, andmeans for actuating said locking means.

31. An elevator having, in combination, a hatchway, two elevator cagesmounted in said hatchWay for adjacent movement side by side, twocounterweights one for each cage mounted in said hatchway on verticalguide rails, said rails being arranged in two parallel and closelyspaced sets, means for connecting said counteriveights, and means fordriving said cages independently when said counterweights aredisconnected, and jointly When said counteriveights are connected.

32. A double unit elevator having, in coinbination, a hatchway, t-Wocages mounted in said hatchivay for adjacent movement, a pair otcounteriveights mounted in said hatchway, means for connecting saidcounterweights, and means for driving said cages jointly orindependently.

33. A double unit elevator having, in combination, a hatchway, tivocages mounted in said hatchivay, a pair of counterweights one for eachcage, means for mechanically connecting` corresponding parts of theelevator structure of each unit, and means for driving said cagesjointly or independently.

In testimony whereof, I have hereunto uixed my signature.

JAMESy DUNLOP.

